Conventional measurement and test equipments employed by telephone service providers customarily contain a variety of conditioning and signal generation capabilities, which enable service and maintenance personnel to command a remote terminal (RT), provided at the terminating end of a digital loop carrier (DLC) system (which extends phone service to subscribers beyond the normal physical limits of a central office), to apply a prescribed number of electrical stimuli to a line (e.g. a (digital) subscriber loop), for the purpose of trouble-shooting the line and measuring its performance.
A non-limitative example of the installation of such equipment in a telephone network is diagrammatically illustrated in FIG. 1, wherein a plurality of (microprocessor-controlled) remote terminals 11 are installed at a plurality of sites geographically remote and dispersed with respect to each other and a central office 12. Each remote terminal 11 includes various resource components, such as tone generation and electrical conditioning circuitry, which, under the control of associated internal processors, selectively transmit test signals to the line, and may also condition the line with prescribed electrical circuit parameters, that allow an associated line monitoring unit to conduct line measurements and thereby determine the current state of the line and its ability to successfully perform as intended. Each remote terminal unit 11 is typically of the type that conforms to computer interface requirements defined in Issue 3 of AT&T Publication KS-23253.
Conventionally, the remote terminal 11 employs a separately dedicated measurement and test unit 11T and a (metallic access) line conditioning unit 11C, each performing a unique set of communication capability and signal processing functions with respect to a selected network line 13 and subscriber termination equipment 15, under the control of one or more host computers, video display terminals (VDTs) or data terminal units (DTUs) 14 at a supervisory site 16. The remote control devices are of the type which have the capability of accessing the remote terminals 11 through attendant modem devices 17, such as industry standard Hayes `AT`-compatible 300/1200 units, that are linked to central office 12. Additionally, via an attendant test set coupled to a direct access test unit (DATU) and pair gain (PG) interface 18, a field technician may gain access to either of the test circuitry or the conditioning circuitry of the remote terminal, and thereby remotely test or condition a line, in substantially the same manner as performed by a maintenance administrator at supervisory site 16.
Associated with each of the resources of a remote terminal, including phone lines for testing and modem access, power supply, ring generators, physical mounting space, etc., is a finite cost. In addition, servicing of the equipment including initial system installation and provisioning, as well as continued maintenance of a variety of testing, conditioning and monitoring equipments all contribute substantially to cost.
In an attempt to reduce cost, some terminal equipment providers produce individual devices, the hardware of which is constrained to perform only a limited subset of testing, monitoring or conditioning functions, that have been selectively tailored to satisfy a `preferred` set of requirements of the user. As a result, should the user request additional performance capability, a new piece of equipment must be purchased and installed. At present, no conventional remote terminal device provides the capability of substantially any function that a user may desire, including each of testing, monitoring and conditioning of a line.